JPH0597165A - Package - Google Patents

Abstract

PURPOSE:To prevent degradation of contents, make their visual check possible and improve the commercial value by a method wherein a packaging material is produced which is provided with a layer on which the powdered zinc oxide having a specific average particle size in diameter is dispersed uniformly at a specific density and a package is made by this packaging material. CONSTITUTION:A package such as made by a bag or container consists of a specific packaging material 1. This packaging material 1 is constituted of a coating film 3 formed by uniformly dispersing the powdered zinc oxide on a synthetic resin film 2 having a good transparency. The powdered zinc oxide is used which has an average particle size of at most 0.2mum in diameter and its dispersion density set within the range of 0.04-0.8g(m<2>.mum). It is preferable to use an epoxy resin or cellulose in the coating film 3 and this coating film may be of a urethane adhesive layer. The above features combine to provide a structure wherein UV rays are absorbed to prevent degradation of the contents on the one hand and visual rays are transmitted to check the contents visually on the other, thereby improving the commercial value of the package.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package such as a packaging bag or a packaging container.

[0002]

2. Description of the Related Art It is well known that some substances such as foods are deteriorated or deteriorated by ultraviolet rays.

In order to block ultraviolet rays and prevent such deterioration, a means for providing a packaging layer with a shielding layer including a metal foil such as aluminum, metal vapor deposition, a coating film mixed with carbon, etc. is adopted. ..

However, according to such means,
Although it can block ultraviolet rays, it also blocks light in the visible light range, so it is not possible to see the contents from the outside with a package that uses the above-mentioned shielding layer, so you can check the contents and There was a difficulty in sex.

There is also a package using a shielding layer mixed with an organic ultraviolet absorber, but the ultraviolet absorbing ability is insufficient,
Has little effect of preventing alteration of contents.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a package having a sufficient ultraviolet ray shielding effect and transmitting visible light.

[0007]

To solve the above problems, in the present invention, zinc oxide fine particles having an average particle diameter of 0.2 μm or less are provided at a density of 0.04 to 0.8 g / (m ² · μm). The packaging body was formed by the packaging material provided with the layers uniformly dispersed.

[0008]

By containing the above zinc oxide fine particles in a specific dispersion density, it is possible to absorb only ultraviolet rays having a wavelength of 400 nm or less and to transmit visible light having a wavelength of 400 nm to 800 nm.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the packaging material forming the package will be described.

As shown in FIG. 1, the packaging material 1 comprises a synthetic resin film 2 having good transparency and a coating film 3 in which fine particles of zinc oxide are uniformly dispersed. This coating film 3
Epoxy resin and cellulose are preferable, and may be an adhesive layer.

As the fine particles, those having an average particle diameter of 0.2 μm or less are used. This is because if it exceeds 0.2 μm, visible light is likely to be scattered and it becomes impossible to see through. A particularly preferred range is 0.01 to 0.05 μm.

The dispersion density of the fine particles is 0.04 to 0.
8 g / (m ² · μm) Especially 0.1-0.4 g / (m ²
-Μm) is preferred. If it is less than 0.04 / (m ² · μm), the ultraviolet ray shielding effect is small, and conversely 0.8 g / (m ² ·
If it exceeds 0.1 μm, not only the physical properties of the mixed layer are affected, for example, the adhesive strength is reduced, but also the visible light transmittance is reduced. The thickness of the layer in which the fine particles are dispersed is not particularly limited, but may be appropriately selected in the range of usually 0.3 to 10 μm, preferably 2 to 10 μm. As a means for dispersing zinc oxide, a known dispersion method such as a ball mill method or a three-roll method may be used, and if necessary, a dispersant such as a silane coupling agent may be added to improve dispersibility.

As shown in FIG. 2, the packaging material 1 may be one in which a zinc oxide layer 4 is provided on the surface of a synthetic resin film 2 by a vapor phase method such as sputtering.

Further, as shown in FIG. 3, the synthetic resin film 2
The zinc oxide fine particles may be kneaded and added during the film formation.

In any case, the average particle size and dispersion density of zinc oxide are the same as above.

FIG. 4 shows a laminate when the packaging material 1 of FIGS. 1 to 3 is actually applied.

As shown in the figure, the laminate 10 comprises a heat seal layer 11, an intermediate reinforcing layer 12, and a surface protective layer 13 laminated by adhesive layers 14 and 14a. Any one of these layers 11, 12, 13, 14, and 14a or a plurality of layers may have any one of the configurations shown in FIGS. 1 to 3.

The layer 11 is a heat-bondable resin layer such as polypropylene, polyethylene, ethylene-vinyl acetate copolymer, polyester, nylon, etc.
In addition to nylon, polypropylene, polyester, and polyethylene, a barrier resin such as ethylene vinyl alcohol or polyvinylidene chloride for improving gas barrier properties, or a metal deposition film provided with a window for visual confirmation may be used.

The layer 13 is made of polyester, nylon, polypropylene or the like. Further, a print layer may be provided.

The layers 14, 14a are preferably polyurethane dry lamination adhesives, but other adhesives may be used as long as they have high adhesive strength.

The polyurethane-based adhesive basically comprises a polyol component and an isocyanate component, and examples of the usable polyol component include polyether polyol, polyester polyol, polyurethane polyol and the like.

As the isocyanate component, toluylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorosodiisocyanate (IPD).
Examples thereof include diisocyanates such as I), modified prepolymers thereof, and burette type adducts.

There are various possible combinations of the polyol component and the isocyanate component, but the following combinations are recommended for food / pharmaceutical packaging.

(I) Polyester urethane diol / I
PDI, XDI trimethylolpropane adduct, or (ii) polyester urethane diol / epoxy resin /
IPDI trimmer.

Of course, the layers 11, 12, 13, 14, 1
4a can be selected according to need.

As shown in FIG. 5, the laminated body 10 has two layers.
When the peripheral portions 15 are heat-sealed in a stack, they become a packaging bag, and as shown in FIG.
It can be heat-sealed and used as a lid.

A more detailed experimental example will be described below.

[Experimental Example 1] 60 μ as a heat-sealing layer
m unstretched polypropylene, 15μ as intermediate layer
Ethylene vinyl alcohol having a thickness of m and polyester having a thickness of 12 μm as a surface protective layer were bonded to each other with a urethane adhesive.

As the adhesive on the surface protective layer side, zinc oxide fine particles having an average particle diameter of 0.01 μm, which have been surface-treated with a silane coupling agent in advance, have a molecular weight of 20,000.
In the dispersion obtained by kneading and dispersing in 0 polyesterurethane diol, IPDI was added until NCO / OH = 2, and then a urethane adhesive diluted with ethyl acetate was prepared and used. The solid coating amount is 4.0 g
/ M ² , and the dispersion density of the zinc oxide fine particles contained in this urethane-based adhesive layer is 0.2 g / (m ² · μ
m).

The light absorption spectrum and oxygen gas permeability (CC
/ M ² .24 hrs atm 23 ° C.) and adhesive strength (g / 15 mm width, T peeling, 100 mm / min) were measured, and the results are shown in FIG. 7.

[Experimental Example 2] The average particle diameter of zinc oxide was 0.1
5 μm and dispersion density of 0.1 g / (m ² · μ
A flat bag similar to that of Experimental Example 1 was formed except that the above-mentioned was set as m).

Comparative Example 1 A flat bag similar to that of Experimental Example 1 was formed except that an adhesive agent containing no zinc oxide was used.

[Comparative Example 2] The average particle size of zinc oxide was 0.3.
A flat bag similar to that of Experimental Example 1 was formed except that the thickness was set to μm.

[Comparative Example 3] The average particle size of zinc oxide was 0.0
A flat bag similar to Experimental Example 1 was formed except that the dispersion density was 5 μm and the dispersion density was 0.03 g / (m ² · μm).

[Comparative Example 4] A flat bag similar to that of Experimental Example 1 was formed except that titanium oxide was used as an ultraviolet absorbing material and the average particle diameter was 0.02 µm.

As is apparent from FIG. 7, in the experimental example, a transmittance of 80% or more is exhibited at a wavelength of 600 nm, and a transmission of 15% or less is stopped at a wavelength of 370 nm or less. Further, the oxygen gas permeability was less than 1 cc, which showed a good gas barrier property, and the adhesive strength was high enough to be satisfied.

On the other hand, Comparative Example 1 shows a light transmission of 80% or more in the ultraviolet to visible region, and although it is transparent, it does not have the ability to block ultraviolet rays.

Although Comparative Example 2 has an ultraviolet ray shielding effect, it is opaque at 65% in the visible light region, and when the average particle diameter becomes large, the irregular reflection of light increases due to the refraction of light.

In Comparative Example 3, since the amount of zinc oxide mixed is too small, the amount of ultraviolet ray transmission increases.

In Comparative Example 4, the ultraviolet absorbing ability of titanium oxide is inferior to that of zinc oxide, so that the ultraviolet shielding property is inferior.

From the above results, zinc oxide powder having an average particle size of 0.2 μm or less is dispersed in the adhesive by an appropriate method,
It can be seen that when the coating film is provided so as to contain 0.04 to 0.8 g / (m ² · μm), a package having an ultraviolet shielding property and transparency, that is, a visible light transmittance can be obtained.

[0043]

[Effect] According to the present invention, as described above, since the packaging body is formed by the packaging material provided with the layer in which the zinc oxide having the specific average particle diameter is uniformly dispersed at the specific dispersion density, Since the deterioration of the contents can be prevented by absorbing the light and the contents can be confirmed by transmitting visible light, the commercial value can be increased.

Further, by using together with a barrier synthetic resin film, it has an ultraviolet ray shielding ability and an oxygen gas and water vapor permeation preventing ability which are not inferior to those of a conventional packaging material formed by laminating aluminum foil. Further, since the metal foil is not included, the used packaging body can be easily incinerated and does not easily cause environmental problems. Further, when zinc oxide fine particles are dispersed in a urethane-based adhesive, the adhesive strength is sufficient to withstand retort sterilization treatment, and microwave cooking is possible. Further, zinc oxide has the advantage that the antistatic property of the package can be expected due to the high conductivity of zinc oxide.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a packaging material forming a packaging body of the present invention.

FIG. 2 is a sectional view showing another example of the above.

FIG. 3 is a sectional view showing still another example of the above.

FIG. 4 is a cross-sectional view showing an application example of a packaging material.

FIG. 5 is a sectional view showing a bag formed of a packaging material.

FIG. 6 is a cross-sectional view of a container formed of packaging material.

FIG. 7 is a table showing results of experimental examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Packaging material 2 Synthetic resin film 3 Coating film 4 Zinc oxide layer 10 Laminated body 11 Heat seal layer 12 Intermediate reinforcement layer 13 Surface protective layer 14, 14a Adhesive layer

Claims (2)

[Claims] 1. A package formed by a packaging material having a layer in which zinc oxide fine particles having an average particle diameter of 0.2 μm or less are uniformly dispersed at a density of 0.04 to 0.8 g / (m ² · μm). body. 2. The package according to claim 1, wherein the layer is a urethane adhesive layer.